1999 Fiscal Year Final Research Report Summary
Studies on the food factors that modulate transport and signal-converting functions of intestinal epithelial cell layer
| Project/Area Number |
09460060
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
食品科学・栄養科学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
SHIMIZU Makoto Graduate School of Agricultural and Life Science, The University of Tokyo, Professor, 大学院・農学生命科学研究科, 教授 (30114507)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Hirohito Graduate School of Agricultural and Life Science, The University of Tokyo, Research associate, 大学院・農学生命科学研究科, 助手 (20270895)
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| Project Period (FY) |
1997 – 1999
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| Keywords | functional food / food factor / intestinal absorption / transporter / tight junction / intestinal epithelial cell / Caco-2 |
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| Research Abstract |
The intestinal epithelium has three major functions, (1) barrier function against orally administered, toxicants or xenobiotics, (2) transport/absorption functions for the uptake of nutrients and functional food substances, and (3) transduction/conversion functions to receive food-derived signals and transfer the information into the body. This suggests that the intestinal epithelium is an important tissue which determines the bioavailability of food-derived functional substances. We have observed, by using an in vitro system with a human intestinal cell line Caco-2, that the intestinal functions could be affected by certain food factors. This study was carried out to reveal the food substances which could modulate the intestinal functions. As an example of food factors that could modulate intestinal barrier functions, we found that a protein from Enokitake (Flammulina velutipes) increased the permeability of the intestinal Caco-2 cell monolayer by opening intracellular tight junctions. This protein, termed TDP, was purified and its cDNA was cloned and sequenced.
TDP was a protein of 31kD and the mechanism for its action was revealed. As transporter-modulatory substances, we found that tea catechins (ECg and EGCg) and lysophosphatidylcholine (LPC) from sesame inhibited intestinal glucose and taurine transporters, respectively. Tea catechins were observed to inhibit glucose transporters (SGLT1 and GLUT) in a competitive manner. On the other hand, LPC was likely to affect the taurine transporter by interacting with lipid bilayers of the cell membrane as well as with the transporter molecule itself. The evidence cleary showing that the food signals from apical side were transferred to the basal side has not yet been obtained. However, recent experiments suggest that certain food substances added to the apical side of the Caco-2 monolayer could induce the secretion by Caco-2 cells of some bioactive substances to the basal side.
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Research Products
(10 results)
